Hi,

My first pattern plane (Great Planes Tracer) is looking like it will weigh in about at most 6 lb. It's nose heavy so simply replacing the current aluminum spinner with plastic, and using a wood prop (current is APC), will shave about 4 oz total... so 5 lb 12 oz is possible. Battery is already aft of the CG. GP states weight range at around 5-5.5 lb. So at 5 b 12 oz it's just 4 oz over GP's limit ... not horrible (considering retracts and large Jett exhaust), but it could be improved.

I am wondering, just how much difference in the "feel" of a plane does an extra 5-10% in weight really make? I know vertical will suffer a proportionate amount, turning radius is slightly bigger, and speed is slightly higher.

... BUT... does it really feel much different in flight ???? Is it worth the effort to shave another few ounces... a bit more is possible by shifting the engine 1/2 inch back, some sanding up front, moving the rudder servo back, etc.

I have no ambitions to hover the plane, so that is a non-issue.

Thanks!

If you are really into weight savings then you need to start in the kit box and not when its already built....Many kits can contain some wood that is not the lightest for the application. In most cases the kit was built using the best possible wood and this is not used when making kits. Some manufacturers are better than others but the wood is still not hand picked.

O good scale can be had for about $40 this will read about 13lbs in 1g increments. These are usually available on Ebay under postage scales. Then weigh every little piece of wood and every component from fuel tanks to wheels.

The next idea is the amount of glue used to the assemble the kit. In most cases we use too much glue especially epoxy....This causes weight gain. Servo choices can lead to weight gains also...Some of the high dollar servos can have a higher weight due to metal gear trains....and many of the std servos are not built with weight as a consideration...Just because the servos is in a certain sized case doesn't mean they weight the same....Servos can vary more than 1/2 oz between models and when you look at 4-5 in a model that adds up to a couple ozs....

The Jett muffler you mentioned? I don't know too much about it but what is its weight compared the motors std muffler?

Battery packs can vary also......
Covering material can drastically affect weight also. Dark colors weigh more than light colors. Some brands weigh more than others.

In the end you will most likely not see the extra 4-8ozs it may be possible the kit manufacture is too optimistic in their box advertisement. On the other hand it may be too heavy and you will know once its in the air.....

My suggestion is too fly it and if it flies too heavy spend some time lightening it.....I'm not really too familiar with the Tracer but in that sized model a 6lb model vs a 5.5lb model should not be a big deal...Now going to a sub 5lb version you might really note the difference. Another thing to realize is that you are adding weight in the form of fuel..its close to an oz for every Fluid Oz so a 12 oz tank is another 3/4lb at takeoff.....So is that extra 1/4 lb really a big deal...I would suggest probably not.....Very few models can fly a plane that has a 1/2 full tank vs a full tank vs a near empty tank and tell WOW this thing flies so great it just lost a 1/2 lb or its too light I must have forgotten to fuel it up? This isn't something that is that visible.....


Weight is a force we all deal with...The struggle to lower weight can carry you into exotic materials, and same with an increase in the price tag of those materials. In the end its up to your skills as a builder and its also a function of what you are willing to do to save that weight. You can lighten things up signifigantly if you are just cautious of the wood, glue and components you choose. Every little bit helps to shave ozs...There is no magic bullet that takes 4-5 ozs out of a small model like that...

Its great you are thinking about it.....Keep up he struggle against weight gain ad your models will fly better...


Troy Newman
Team JR

Thanks Troy.

The Jett muffler is about 1.5 oz heavier than the stock OS46FX muffler.

I currently have 3 oz of lead in the tail. So I have some room to wiggle around and save a bit. Removing 2 oz from the nose (replace heavy prop and spinner) will permit about one oz of lead to be removed. So that's 3 gone. Some of the remaining 2 oz of lead can be eliminated by moving a servo back, and pushing the battery a bit further back. So I think I can shed 5 oz with out much effort. And I get a stiffer rudder setup in the process. That shouldn't bee too bad at all.

To get lower, would have required some thought when it was still in the box.... you're correct on that point.

Hi,

I am not sure if you would consider using mini metal gear servos instead.

For instant, Hitec 85MG is only .9oz each, and rates up to 61oz, then you can also use micro servo on the throttle.

Loose the big tires, and find some smaller and lighter replacements.

Just an idea...for pattern it's nice to fly around nicely at half to 2/3 throttle, and save the rest of the throttle curve for vertical pull.

Just an idea.

Got the light tires.

Your right about the throttle servo, a small servo would save near an ounce.

Thanks.

Stick with the APC.
Change to a lightweight battery and place it towards the tail getting rid of the lead.
Change to light foam wheels.
Fly it! and don't worry, you won't notice the difference anyway!